1. Technical Field
The invention relates to a transparent optical element which is provided with dual light-polarizing effect, and also to a process for manufacturing such transparent optical element. It may be implemented in particular to ophthalmic applications.
2. Description of the Related Art
Spectacle eyeglasses which are provided with linear light-polarizers are well known, in particular sunglasses. For example, such spectacle eyeglasses are adapted for reducing or suppressing glaring light produced by reflecting surfaces oriented either vertically or horizontally. Thus, wearing such eyeglasses which are provided with horizontally oriented linear light-polarizers, suppressing vertically oriented polarized light, allows car-driving in city environment without being dazzled by light reflected on shopfront glazings. In another example, eyeglasses which are provided with vertically oriented linear light-polarizers, suppressing horizontally oriented polarized light, allow vision through the water surface of a lake, because light reflected from the water surface at Brewster incidence value is suppressed by the polarizer. Such latter eyeglasses also reduce light reflected by snow as perceived by skiers, or light reflected on road surfaces.
But conditions exist where eyeglasses provided with linear light-polarizers hinder the wearer from seeing some elements and perceiving the corresponding visual information. For example, light produced by liquid crystal display is commonly polarized, and wearing eyeglasses which are provided with polarizers capable of suppressing polarized light of the same type may make it impossible to read the display under certain circumstances. This may be especially harmful for drivers when polarizing sunglasses hinder from reading driving information displayed on an electronic dashboard of the car. In other cases, people relying on such display may not be able to see the information while having a direct line-of-sight with it, or even while keeping it in one's hand if the polarized light emitted by it has a wrong orientation with regard to the glasses' polarization axis.
Then, an object of the present invention consists in providing transparent optical elements which do not have such drawbacks, while still providing protection against dazzling.
Another object of the invention consists in providing transparent optical elements which are adapted for being efficient with variable light polarization conditions. More particularly, optical elements according to the invention allow seeing objects producing light with different polarization features without changing the head position.